IEEE 802.11 describes a communication architecture, which may enable computing devices to communicate via wireless local area networks (WLANs). One of the building blocks for the WLAN is the basic service set (BSS). A BSS may comprise a plurality of computing devices, or stations (STA), which may communicate wirelessly via one or more RF channels within a coverage area. The span of a coverage area may be determined based on the distance over which a source STA may transmit data via an RF channel, which may be received by a destination STA.
An independent BSS (IBSS) refers to a BSS, which comprises a set of STAs, which may communicate with each over within the coverage area for the BSS. The IBSS is identified by a BSS identifier (BSSID) and a service set identifier (SSID). In an IBSS each STA may engage in direct communication with any of the other STAs within the IBSS. An IBSS may be referred to as an ad hoc network.
To facilitate communication within the IBSS, each STA may negotiate a set of network parameters to utilize when communicating with other STAs in the IBSS. These network parameters may include frequency spectrum management for RF channel assignment, determination of supported data rates and quality of service (QoS) parameters, for example. Each STA also attempts to synchronize its operations to a clock source, which is common to the STAs within the IBSS.
The negotiation of network parameters and timing synchronization among the STAB typically involves the exchange of beacon frames. At various time instants, one or more STAB within the IBSS may transmit a beacon frame. A transmitted beacon frame may be received by each of the other STAB within the IBSS. The beacon frame may contain information elements, which specify a set of network parameters and enable timing synchronization among the STAB. Each transmitted beacon frame contains a timestamp value, which is determined based on a timing synchronization function (TSF) executing within the STA that transmitted the beacon frame.
Since an STA may receive a plurality of beacon frames within a time interval, referred to as a nominal beacon window, the receiving STA determines which one, if any, of the received beacon frames is to be adopted. Upon receiving a beacon frame, the receiving STA compares the timestamp value contained within the received beacon frame, with a time value generated by the TSF. When the received timestamp value is greater than the time value generated by the TSF, the TSF time value is set to a value equal to the received timestamp value. In addition, the STA adopts the network parameters contained within the beacon frame. In this regard, the receiving STA time synchronizes to the TSF clock of the STA, which transmitted the beacon frame. In addition, the receiving STA will utilize network parameters contained within the beacon frame when communicating with other STAB within the IBSS.
When the received timestamp value is less than or equal to the time value generated by the TSF, the STA adopts neither the timestamp value or the network parameters contained within the received beacon frame. In this regard, the receiving STA determines to neither time synchronize to the STA, which transmitted the beacon frame, or to utilize network parameters contained within the beacon frame when communicating with other STAs within the BSS.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.